If the boat is
sculled by rowers, each with two oars, the combination is called a
quad scull. In that boat the riggers apply forces symmetrically. However most rowing clubs cannot afford to have a four-seat quad-only format delicate boat, which might be rarely used and instead generally opt for versatility in their fleet by using stronger "standard, versatile" shells to be rigged as either boat. Aside from the structural strength, crossways, boats rigged for either format or sweep-oar use tend to have larger mountings/fixings for their riggers than classic, sculling-only vessels. ==See also==